Allow COM based API to discover and check entrypoints without [shader] attribute. (#3914)

* Allow COM based API to discover and check entrypoints without [shader] attribute.

* Undo changes.

* More comments.

7 files changed, 129 insertions, 7 deletions

diff --git a/build/visual-studio/slang-unit-test-tool/slang-unit-test-tool.vcxproj b/build/visual-studio/slang-unit-test-tool/slang-unit-test-tool.vcxproj
index 2798b80e4..c1d6f395d 100644
--- a/build/visual-studio/slang-unit-test-tool/slang-unit-test-tool.vcxproj
+++ b/build/visual-studio/slang-unit-test-tool/slang-unit-test-tool.vcxproj
@@ -294,6 +294,7 @@
     <ClCompile Include="..\..\..\tools\slang-unit-test\unit-test-crypto.cpp" />

     <ClCompile Include="..\..\..\tools\slang-unit-test\unit-test-default-matrix-layout.cpp" />

     <ClCompile Include="..\..\..\tools\slang-unit-test\unit-test-file-system.cpp" />

+    <ClCompile Include="..\..\..\tools\slang-unit-test\unit-test-find-check-entrypoint.cpp" />

     <ClCompile Include="..\..\..\tools\slang-unit-test\unit-test-find-type-by-name.cpp" />

     <ClCompile Include="..\..\..\tools\slang-unit-test\unit-test-free-list.cpp" />

     <ClCompile Include="..\..\..\tools\slang-unit-test\unit-test-io.cpp" />

diff --git a/build/visual-studio/slang-unit-test-tool/slang-unit-test-tool.vcxproj.filters b/build/visual-studio/slang-unit-test-tool/slang-unit-test-tool.vcxproj.filters
index 3fd04c077..f3a9c85f8 100644
--- a/build/visual-studio/slang-unit-test-tool/slang-unit-test-tool.vcxproj.filters
+++ b/build/visual-studio/slang-unit-test-tool/slang-unit-test-tool.vcxproj.filters
@@ -38,6 +38,9 @@
     <ClCompile Include="..\..\..\tools\slang-unit-test\unit-test-file-system.cpp">

       <Filter>Source Files</Filter>

     </ClCompile>

+    <ClCompile Include="..\..\..\tools\slang-unit-test\unit-test-find-check-entrypoint.cpp">

+      <Filter>Source Files</Filter>

+    </ClCompile>

     <ClCompile Include="..\..\..\tools\slang-unit-test\unit-test-find-type-by-name.cpp">

       <Filter>Source Files</Filter>

     </ClCompile>

diff --git a/slang.h b/slang.h
index 4014be401..4ed37d88c 100644
--- a/slang.h
+++ b/slang.h
@@ -4949,6 +4949,13 @@ namespace slang
         /// Get the unique identity of the module.
         virtual SLANG_NO_THROW const char* SLANG_MCALL getUniqueIdentity() = 0;
 
+        /// Find and validate an entry point by name, even if the function is
+        /// not marked with the `[shader("...")]` attribute.
+        virtual SLANG_NO_THROW SlangResult SLANG_MCALL findAndCheckEntryPoint(
+            char const* name,
+            SlangStage stage,
+            IEntryPoint** outEntryPoint,
+            ISlangBlob** outDiagnostics) = 0;
     };
     
     #define SLANG_UUID_IModule IModule::getTypeGuid()
diff --git a/source/slang/slang-check-impl.h b/source/slang/slang-check-impl.h
index 55edba6b9..e6e980fe8 100644
--- a/source/slang/slang-check-impl.h
+++ b/source/slang/slang-check-impl.h
@@ -2773,4 +2773,7 @@ namespace Slang
         SemanticsDeclVisitorBase* visitor,
         Decl* decl,
         DeclCheckState              state);
+
+    RefPtr<EntryPoint> findAndValidateEntryPoint(
+        FrontEndEntryPointRequest* entryPointReq);
 }
diff --git a/source/slang/slang-compiler.h b/source/slang/slang-compiler.h
index 14d4054c4..014b678f5 100755
--- a/source/slang/slang-compiler.h
+++ b/source/slang/slang-compiler.h
@@ -1338,6 +1338,20 @@ namespace Slang
             return SLANG_OK;
         }
 
+        virtual SLANG_NO_THROW SlangResult SLANG_MCALL findAndCheckEntryPoint(
+            char const* name,
+            SlangStage stage,
+            slang::IEntryPoint** outEntryPoint,
+            ISlangBlob** outDiagnostics)
+        {
+            ComPtr<slang::IEntryPoint> entryPoint(findAndCheckEntryPoint(UnownedStringSlice(name), stage, outDiagnostics));
+            if ((!entryPoint))
+                return SLANG_FAIL;
+
+            *outEntryPoint = entryPoint.detach();
+            return SLANG_OK;
+        }
+
         virtual SlangInt32 SLANG_MCALL getDefinedEntryPointCount() override
         {
             return (SlangInt32)m_entryPoints.getCount();
@@ -1481,6 +1495,7 @@ namespace Slang
         };
 
         RefPtr<EntryPoint> findEntryPointByName(UnownedStringSlice const& name);
+        RefPtr<EntryPoint> findAndCheckEntryPoint(UnownedStringSlice const& name, SlangStage stage, ISlangBlob** outDiagnostics);
 
         List<RefPtr<EntryPoint>>& getEntryPoints() { return m_entryPoints; }
         void _addEntryPoint(EntryPoint* entryPoint);
diff --git a/source/slang/slang.cpp b/source/slang/slang.cpp
index 6d40b46a2..0db833c7a 100644
--- a/source/slang/slang.cpp
+++ b/source/slang/slang.cpp
@@ -3987,13 +3987,6 @@ void Module::setName(String name)
 
 RefPtr<EntryPoint> Module::findEntryPointByName(UnownedStringSlice const& name)
 {
-    // TODO: We should consider having this function be expanded to be able
-    // to look up and validate possible entry-point functions in teh module
-    // even if they were not marked with `[shader(...)]` in the source code.
-    //
-    // With such a change the function would probably need to accept a stage
-    // to use and a sink to write validation errors to.
-
     for(auto entryPoint : m_entryPoints)
     {
         if(entryPoint->getName()->text.getUnownedSlice() == name)
@@ -4003,6 +3996,41 @@ RefPtr<EntryPoint> Module::findEntryPointByName(UnownedStringSlice const& name)
     return nullptr;
 }
 
+
+RefPtr<EntryPoint> Module::findAndCheckEntryPoint(
+    UnownedStringSlice const& name,
+    SlangStage stage,
+    ISlangBlob** outDiagnostics)
+{
+    // If there is already an entrypoint marked with the [shader] attribute,
+    // we should just return that.
+    //
+    if (auto existingEntryPoint = findEntryPointByName(name))
+        return existingEntryPoint;
+
+    // If the function hasn't been marked as [shader], then it won't be discovered
+    // by findEntryPointByName. We need to route this to the `findAndValidateEntryPoint`
+    // function. To do that we need to setup a FrontEndCompileRequest and a FrontEndEntryPointRequest.
+    //
+    DiagnosticSink sink(getLinkage()->getSourceManager(), DiagnosticSink::SourceLocationLexer());
+    FrontEndCompileRequest frontEndRequest(getLinkage(), StdWriters::getSingleton(), &sink);
+    RefPtr<TranslationUnitRequest> tuRequest = new TranslationUnitRequest(&frontEndRequest);
+    tuRequest->module = this;
+    tuRequest->moduleName = m_name;
+    frontEndRequest.translationUnits.add(tuRequest);
+    FrontEndEntryPointRequest entryPointRequest(
+        &frontEndRequest,
+        0,
+        getLinkage()->getNamePool()->getName(name),
+        Profile((Stage)stage));
+    auto result = findAndValidateEntryPoint(&entryPointRequest);
+    if (outDiagnostics)
+    {
+        sink.getBlobIfNeeded(outDiagnostics);
+    }
+    return result;
+}
+
 void Module::_addEntryPoint(EntryPoint* entryPoint)
 {
     m_entryPoints.add(entryPoint);
diff --git a/tools/slang-unit-test/unit-test-find-check-entrypoint.cpp b/tools/slang-unit-test/unit-test-find-check-entrypoint.cpp
new file mode 100644
index 000000000..371c8ae81
--- /dev/null
+++ b/tools/slang-unit-test/unit-test-find-check-entrypoint.cpp
@@ -0,0 +1,65 @@
+// unit-test-translation-unit-import.cpp
+
+#include "../../slang.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "tools/unit-test/slang-unit-test.h"
+#include "../../slang-com-ptr.h"
+#include "../../source/core/slang-io.h"
+#include "../../source/core/slang-process.h"
+
+using namespace Slang;
+
+// Test that the IModule::findAndCheckEntryPoint API supports discovering 
+// entrypoints without a [shader] attribute.
+
+SLANG_UNIT_TEST(findAndCheckEntryPoint)
+{
+    // Source for a module that contains an undecorated entrypoint.
+    const char* userSourceBody = R"(
+        float4 fragMain(float4 pos:SV_Position) : SV_Position
+        {
+            return pos;
+        }
+        )";
+
+    auto moduleName = "moduleG" + String(Process::getId());
+    String userSource = "import " + moduleName + ";\n" + userSourceBody;
+    ComPtr<slang::IGlobalSession> globalSession;
+    SLANG_CHECK(slang_createGlobalSession(SLANG_API_VERSION, globalSession.writeRef()) == SLANG_OK);
+    slang::TargetDesc targetDesc = {};
+    targetDesc.format = SLANG_HLSL;
+    targetDesc.profile = globalSession->findProfile("sm_5_0");
+    slang::SessionDesc sessionDesc = {};
+    sessionDesc.targetCount = 1;
+    sessionDesc.targets = &targetDesc;
+    ComPtr<slang::ISession> session;
+    SLANG_CHECK(globalSession->createSession(sessionDesc, session.writeRef()) == SLANG_OK);
+
+    ComPtr<slang::IBlob> diagnosticBlob;
+    auto module = session->loadModuleFromSourceString("m", "m.slang", userSourceBody, diagnosticBlob.writeRef());
+    SLANG_CHECK(module != nullptr);
+
+    ComPtr<slang::IEntryPoint> entryPoint;
+    module->findAndCheckEntryPoint("fragMain", SLANG_STAGE_FRAGMENT, entryPoint.writeRef(), diagnosticBlob.writeRef());
+    SLANG_CHECK(entryPoint != nullptr);
+
+    ComPtr<slang::IComponentType> compositeProgram;
+    slang::IComponentType* components[] = { module, entryPoint.get() };
+    session->createCompositeComponentType(components, 2, compositeProgram.writeRef(), diagnosticBlob.writeRef());
+    SLANG_CHECK(compositeProgram != nullptr);
+
+    ComPtr<slang::IComponentType> linkedProgram;
+    compositeProgram->link(linkedProgram.writeRef(), diagnosticBlob.writeRef());
+    SLANG_CHECK(linkedProgram != nullptr);
+
+    ComPtr<slang::IBlob> code;
+    linkedProgram->getEntryPointCode(0, 0, code.writeRef(), diagnosticBlob.writeRef());
+    SLANG_CHECK(code != nullptr);
+
+    auto codeSrc = UnownedStringSlice((const char*)code->getBufferPointer());
+    SLANG_CHECK(codeSrc.indexOf(toSlice("fragMain")) != -1);
+}
+